Highly reliable online system

摘要

A highly reliable online system is disclosed which is provided with a backup computer center (sub-online system) in addition with an original computer center (main online system) in order to improve the reliability of the online system. With respect to the database, the main online system is provided with an original database (main database) while the sub-online system is provided with a backup database (sub-database) which is a duplicate of the main database. The main online system and the sub-online system are connected through a transmission path. Information on an update performed in the main database is transferred to the sub-online system through the transmission path to thereby update the sub-database in a manner similar to the main database. Terminal units are normally connected to the main online system, wherein the main database is updated by transactions inputted from the terminals. When a failure occurs in the main online system, the terminals are changed over to be connected to the sub-online system to allow transaction processing to be continued. Further, there are provided a control system for synchronizing contents between the main database and the sub-database when the original computer center is changed over to the backup computer center, a recovery system for recovering the main database or the sub-database from failures and an integration system for integrating both the main database and the sub-database when they are independently updated due to a failure in the transmission path or the like.